The present invention relates generally to transport apparatus, and more particularly, is directed to transport apparatus for large network telecommunication equipment.
The manner in which telephones at different locations are connected to each is well known. Basically, one telephone is connected to a first Central Office, either directly or indirectly connected through a Remote Terminal. The first Central Office is connected to a second Central Office, which is connected to the other telephone directly or indirectly through another Remote Terminal. The Central Offices and Remote Terminals provide for switching of the telephone signals and enhancement of the telephone signals.
Generally, the Central Offices use digital access and cross-connect systems (DACS) as one of the switching units. It is noted that the signal from a telephone is at a relatively low rate. By the time it arrives at the cross-connect system, it has been converted to a higher rate of a direct sequence (DS) waveform, such as DS1 and DS3. DS waveforms are pseudorandom digital streams generated by digital techniques and transmitted without significant spectral filtering. The cross-connect system receives the DS waveform signals and cross-connects the signals in a large matrix. The signals are then sent back out through different interface bays with DS1 and DS3 waveform formats. The interface bays are connected with external equipment, either within the same Central Office, other Central Offices, or Remote Terminals.
In the cross-connect system, there are numerous interface bays that receive and transmit the DS1 and DS3 format signals, with the interface bays being connected to a switch complex that provides re-routing or cross-connecting of the signals. For example, there may be an interface bay that accepts only DS1 format signals, an interface bay that accepts only DS3 format signals, and an interface bay that accepts both DS1 and DS3 format signals. The interface bays are connected to the switch complex by twisted bundles of copper wires. The switch complex generally includes power units, controllers and the like.
All of the equipment at the Central Office, that is, the large network telecommunication equipment, such as the digital cross-connect systems, are mounted on metal network bay frames or racks. Each frame is generally formed by two upright flanges, a connecting base which connects the lower ends of the upright flanges, and a top support which connects the upper ends of the upright flanges. Thus, there is front and rear access to the telecommunication equipment mounted on the frames. Generally, such frames are large, having a width ranging from about nineteen inches to twenty six inches, and a height ranging from about seven feet to about eleven feet, six inches. The DACS equipment is designed to fit in a twenty-six inch wide, seven foot high frame, regardless of the frame size.
For example, for a smaller system such as the DACS IV-2000 (256) system sold by AT&T, the start-up shipment is comprised of one switch bay where all of the switch and controller modules are mounted, and one full interface bay and two half cable storage bays. Each bay utilizes one frame, so that there are four frames coupled together. For the larger DACS IV-2000 (512) system, the start-up shipment is comprised of two switch bays and a main controller bay and two cable storage bays. In such case, the amount of cabling is proportionally larger.
Thus, for large network equipment, such as the DACS IV-2000 sold by AT&T, a large amount of cabling is required between the modules within the switch complex and between the switch complex and the cable storage bays. In terms of workmanship and quality, it is desirable to have the cables pre-installed in the factory, since the installation is performed by highly trained and specialized workers in a controlled environment. In addition, the quality control inspection and testing processes at the manufacturing location are always tightly monitored.
Thus, to ensure such reliability and the highest integrity within the switch complex, the switch complex cabling is completed in the factory. For the interface bay cables, one end thereof is installed in the factory to ensure reliability. The other end is left unconnected for field connection.
However, the frames for the switch complex and cable storage bays are rigidly connected together, in an in-line manner, and are shipped in this manner, with the cables connected as discussed above. Thus, the resulting size of the initial shipment package becomes an in-line arrangement of five seven foot network bay frames for the DACS IV-2000 (512), with a total footprint of ten feet, ten inches by one foot. This, however, presents a problem in transport, due to limitations of elevator size and office aisle clearance, particularly around tight corners.